Monday, February 25, 2013

AMD's Chance

So, back to the previous topic.

Essentially, AMD has an architecture that's not keeping up with Intel. They're pushing an architecture that doesn't have as good a single threaded performance, but has potential to handle more threads.

Lets face it that's not always the case. A core i5 CPU's quad core 4-issue wide setup will have great IPC ratio and enough parallelism for most tasks.

The core i3, is similar to the core i5. They run the same architecture (ivybridge today). One big difference is core i3's have hyperthreading enabled giving 2 real cores, 4 logical cores. Core i5 runs 4 real cores without hyperthreading. There's also a cache size difference to add to this, and core i3 has no turbo function.

Now lets see how this affects us (consumers). I need to spend $120-130 for a core i3, and $180-$190 for core i5. 

This puts AMD's 8 core (4 module) CPU against the i5. The i5 having great single threaded performance and significant multiprocessing capability. 8 cores do not give as much of a boost as many would think. Most apps aren't that well multithreaded. The single threaded performance of the i5 punches well enough above AMD's 8350 making the 8 core processor a tough sell in many areas.

The AMD 6 core piledriver (also ~$120) is structurally very similar to their 8 core chip, single core performance doesn't take a hit here. Core i3 does though when compared to i5. The main strength of intel core gets lost on i3. The cut in cache and lack of turbo lets AMD's "6" core FX 6300 catch up in single threaded performance. The multiprocessing advantage of the AMD part is clear though. While today we don't utilize more than 4 cores very well, the jump from 2 cores is significant enough. 2 core-i3 cores to 6-vishera? Good enough jump.

Synopsis: AMD maintained high multiprocessing capability without sacrificing much single core performance on their lower end parts. When they were within spitting distance of their rival in single threaded performance, they maintained the edge in multithreading/multiprocessing. They will need to keep this edge, while they improve their core performance.

With tax season done, I'm keenly eyeing an AMD deal in the store now. For a while, i didn't think that I would.

Thursday, February 21, 2013

x86 Desktop Landscape

AMD, Where art thou...
On a benchmark chart?

It's February 2013. Ivy bridge dominates intel's landscape - celeron, pentium, core i3/i5/i7 are all derivative, and that's a good thing, since it's a pretty damn good core revision.

AMD has been having a hard time since Intel jumped on to Core architecture - which was derived from Pentium-M. Pentium-M's beginnings were not with netburst used in Pentium 4/Pentium D, but from Pentium 3's tualatin. This was the rival that was getting beaten by the AMD Athlon that preceded the Athlon XP.

So Intel after investing heavily in netburst, realized they had a killer core with the Pentium III derived Pentium-M, and pushed core architecture and core 2 nixing the netburst strategy - good call.

Many companies tend to have individuals that push their projects - sometimes, when there's too heavy an investment in a product that isn't as good as an existing service they stick with the newer not-as-good product. The individuals in charge of that new product line or those deciding to keep it going, spin tales to investors of how much more it will earn. Why? Because if they go back to develop the older product, they believe they're admitting a mistake.

What is AMD spinning now with bulldozer? The only thing it's pushing now, is that it's cheap. Phenom II (aka stars core) offered better single core performance overall. Today a phenom II x6 1100t - a 3.2GHz 6 core (stars) cpu, can stand toe to toe, even trading blows with AMD's top of the line vishera core - 8350. A 4.0GHz part.

Obviously, AMD's stars based core was getting long in the tooth, but bulldozer isn't the (full?) answer. It's great for multiple threads of integer processing, but it's not 8 full cores. It's 4 modules, featuring a pair of cores each that share some units (like floating point), giving reduced performance.

To be fair, it's not BAD. I think we would have had better CPUs though if Phenom II cores were further developed. The fallout is pretty harsh though. AMD's top end "8"-core, 8350 CPU is selling for $200 - A far cry from the Athlon 64 days of thousand dollar CPUs. Problem is, the 8-core (4-module) AMD cpu still doesn't contend well enough against Intel core i5 quad cores.

There is a light for AMD though against core i3, there's the 6 core processors. while core i3 exhibits strong single core performance, the 6-core (3 module) AMD 6200/6300 isn't convincingly behind, and packs a wallop in multithreaded/multiprocessing loads. Of course - keep in mind if going the bulldozer route, there are CPU scheduling patches you should apply for your OS - after all, why run two floating point threads on the same module and have them fight for the one FPU?

AMD's patches:

AMD's blog post on CPU core scheduling:

Lets not start getting into TDP here...

Wednesday, February 20, 2013


goto 10...

So, starting this blog and haven't much in mind.
Or to be precise, there's a lot on my mind, but where to start? where's my "10"?
Guess I'll just have to post stuff as it comes to mind...